Unveiling Semiconductor Nanostructured Based Holmium-Doped ZnO: Structural, Luminescent and Room Temperature...

This research work describes the synthesis of ZnO nanostructures doped with Ho³⁺ ions using a conventional sol-gel synthesis method. The nanostructured produced exhibited a wurtzite hexagonal structure in both ZnO and ZnO:Ho³⁺ (0.25, 0.5, 0.75 mol%) samples. The change in morphology with addition of Ho³⁺ dopants was observed, which was assigned to Ostwald ripening effect occurring during the nanoparticles' growth. The photoluminescence emission properties of the doped samples revealed that Ho³⁺ was emitting through its electronic transitions. Moreover, reduced surface defects were observed in the Holmium doped samples whose analysis was undertaken using an X-ray Photoelectron Spectroscopy (XPS) technique. Finally, enhanced room temperature ferromagnetism (RT-FM) for Ho³⁺-doped ZnO (0.5 mol%) samples with a peak-to-peak line width of 452 G was detected and found to be highly correlated to the UV-VIS transmittance results.